Fisting pornography features the insertion of an entire hand into a performer vagina or anus. This technique may include the use of a simulacrum, or artificial vagina. When all regions of the face are included, facial cum shots comprise approximately 62% of scenes where external ejaculation occurs. Amateur porn has been called one of the most profitable and long-lasting genres of pornography. In pornography, depictions of lesbian sex form a popular subgenre, directed toward a male heterosexual and female homosexual audience. Masturbation has been depicted in art since prehistoric times and is mentioned and discussed in very early writings. Sex experts have praised various techniques that the performer momporn can use during fellatio to increase their partner pleasure. The exact source and nature of the fluid continue to be a topic of debate among medical professionals, which is hentai porn also related to doubts over the existence of the G-Spot. Ethnic pornography is a genre of pornography that features performers of specific ethnic groups, or depictions of interracial sexual activity. Lesbian pornography made for women is usually made by women, and usually features women who identify as lesbian or bisexual. Transsexual porn star Wendy Williams has stated that transsexual porn is classified as Straight Specialty. It may involve sexual attraction to women who are pregnant or appear pregnant, attraction to lactation, or attraction to particular stages of pregnancy such as impregnation or childbirth. Crying pornography that features participating gaysex actors crying. Anal sex or anal intercourse is generally the insertion and thrusting of the erect penis into a person anus, or anus and rectum, for sexual pleasure. The buttocks in human females thus contain more adipose tissue than in males, especially after puberty. Pleasure for the giver during anilingus is usually based more on the principle of the act. Others may also use vibrators and other sexual devices more commonly associated with female masturbation.